A concave lens of 20 cm focal length has an object kept at a distance of 60 cm in front of the mirror. Compute the image distance.

A concave lens of focal length 15 cm forms an image 10cm from the lens. How far is the object placed from the lens? Draw the ray-diagram.

An object 60 cm from a lens gives a virtual image at a distance of 20 cm in front of the lens. What is the focal length of the lens? Is the lens converging or diverging? Give reasons for your answer.

A concave lens has focal length 20 cm. At what distance should the object from the lens be placed so that it forms an image at 10 cm from the lens?

Calculate the image distance for an object of height 12 mm at a distance of 0.20 m from a concave lens of focal length 0.30 m?